Snapshot backscatter radiography system and protocol

ABSTRACT

A snapshot backscatter radiography (SBR) system and related method includes at least one penetrating radiation source, and at least one radiation detector. The radiation detector is interposed between an object to be interrogated and the radiation source. The radiation detector transmits a portion of the forward radiation from the radiation source to the object. A portion of the transmitted radiation is scattered by the object and is detected by the detector. An image of the object can be obtained by subtracting the forward radiation detected at the detector, or an estimate thereof, from a total of all radiation detected by the detector. Integrated circuit inspection, land mine detection, and luggage or cargo screening systems can be SBR based.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

1. Field of the Invention

The invention relates to radiography, and more particularly toradiography systems which combine aspects of both transmission andbackscatter radiography, and methods thereof.

2. Background

In many industrial, military, security or medical applications, imagesof the internal structure of objects is required. Radiography is oftenused for imaging. Radiography generally comprises either conventionaltransmission radiography or backscatter radiography.

FIG. 1 is a schematic illustrating the configuration used forconventional transmission radiography. In conventional radiography, animage is formed by transmitting radiation from a radiation generator 105through an internal detail 110 within object 130. Attenuated radiationis received by a radiation detector 115 which is disposed on the side ofthe object opposite to that of the radiation generator 105. In the caseof tomography, the object 130 is generally rotated about axisperpendicular to the plane of the figure.

FIG. 2 is a schematic illustrating the configuration used forbackscatter radiography. Unlike conventional radiography which relies ontransmission, in backscatter radiography radiation is scattered byinternal detail 210 within object 230. In backscatter radiography, theradiation generator 205 and radiation detector 215 are on the same sideof the object 230. All backscatter radiography techniques allowone-sided imaging of the object since the radiation generator 205 andthe radiation detector 215 arc located on the same side of the object230. This is the same imaging configuration that people and animals usefor optical viewing of the surroundings. Because of the absence of arefraction process for the penetrating radiation in backscatterradiography, image-gathering lenses cannot be used.

In backscatter radiography, illumination of an entire region of theobject to be interrogated in a single snapshot has generally only beenpossible using a pinhole, coded aperture, or a restriction positionedbetween the object and the radiation detector. This generally results ineither extremely inefficient sensing of the radiation, or theintroduction of substantial image-obscuring structured noise, thusrequiring large exposure times for typical radiation sources. Analternative includes use of a scanning pencil or fan beam forilluminating a temporal sequence of points or lines on the objectsurface. This also yields long exposure times and decoding algorithmshaving long calculation times, besides requiring an expensive scanningapparatus.

The equivalent of an optical snapshot camera capable of implementationusing relatively inexpensive components which would provide high imageresolution and a short exposure time would be desirable for applicationswhich require one-sided imaging of the internal structure of objects.

SUMMARY OF THE INVENTION

A snapshot backscatter radiography (SBR) system and related methodincludes at least one penetrating radiation source and at least oneradiation detector. The radiation detector is interposed between theobject to be interrogated and the radiation source. The radiationdetector transmits a portion of radiation received from the radiationsource to the object. The object backscatters at least a portion of theradiation it receives, with a portion of the scattered radiation beingdetected by the detector.

Generally, reference (base) radiation data is obtained by using thesystem without the object present in a low backscatter environment. Thebase data is then preferably stored prior to interrogating the object.The base data can then be subtracted from the total radiation datameasured by the detector which includes information from both thedetector structure and spatial variation of the radiation source field,as well as the object structure. This permits generation of an image ofthe object. The system can interrogate a wide variety of objects orvolumes, such as buried or otherwise unobservable volumes suspected ofcontaining a bomb (e.g. landmine), luggage or cargo, or integratedcircuits.

The penetrating radiation source can comprise an x-ray, gamma ray,neutron or an electron beam source. The detector can comprise aphotostimuable phosphorous-based image plate or an amorphous siliconpanel. The detector can also include a digitizing field screen. Thesystem preferably includes a computer for receiving radiation data fromthe detector and for performing data and image processing

A radiation source controller is also preferably provided. The radiationsource controller can permit the system to produce 3 dimensional (3-D)radiation data which permits the generation of a 3-D image of theobject. For example, the radiation source controller can direct theradiation source to provide multiple bursts at varying radiation energyor temporal variation of a radiation energy spectrum.

The system can also include one or more collimating sheets disposedbetween the object and the detector. Collimating sheet(s) can be used toimprove resolution or help isolate a lateral migration component of thebackscattered radiation.

A snapshot backscatter radiography (SBR) based land mine detectionsystem includes at least one penetrating radiation source and at leastone radiation detector, wherein the radiation detector is interposedbetween a volume of earth to be interrogated and the radiation source.The radiation detector transmits a portion of incident radiation fromthe radiation source to an object buried in the volume of earth, whereina portion of radiation scattered by the object is detected by thedetector. The radiation source preferably comprises an x-ray source. Theradiography system can include a vehicle to add mobility to the system.

The invention can also be used for luggage or cargo screening, or as anintegrated circuit inspection tool. In the case of the integratedcircuit inspection tool the detector can comprise a CCD array detector.In a preferred embodiment the penetrating radiation source providesselectable radiation energy. This permits generation of a 3-D image ofthe object interrogated to obtained without physically scanning thesystem or the object by compiling radiation data at a plurality ofradiation energies.

A snapshot backscatter radiography (SBR) method for imaging an objectincludes the steps of directing penetrating forward radiation through adetector to an object to be interrogated, the detector transmitting aportion of the penetrating radiation to the object, wherein the objectbackscatters radiation toward the detector. By processing the radiationdata collected by the detector an image of the object can be generated.When at least one collimating sheet is disposed between the object andthe detector, the method can include the step of collimating the forwardradiation and/or the backscattered radiation. A deconvolving imageenhancement technique can in addition be applied to reduce imageblurring.

BRIEF DESCRIPTION OF THE DRAWINGS

A fuller understanding of the present invention and the features andbenefits thereof will be accomplished upon review of the followingdetailed description together with the accompanying drawings, in which:

FIG. 1 is a schematic illustrating the configuration used forconventional transmission radiography.

FIG. 2 is a schematic illustrating the configuration used forconventional backscatter radiography.

FIG. 3 is a schematic illustrating the configuration used for snapshotbackscatter radiography, according to an embodiment of the invention.

FIG. 4 is schematic illustrating an alternate SBR configurationincluding collimators which emphasizes the lateral migration signalcomponent of the backscatter radiation signal, according to anembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

A snapshot backscatter radiography (SBR) system and related methodincludes at least one penetrating radiation source, and at least oneradiation detector. The radiation detector is interposed between theobject to be interrogated and the radiation source so that the radiationdetector receives and detects the radiation from the radiation sourcebefore transmitting a portion thereof to the object to be interrogated.The object backscatters a portion of the transmitted radiation. Aportion of the backscattered radiation is detected by the detector. Animage of the object can be obtained by subtracting the incidentradiation data, or an estimate thereof, from the total detector datacollected. Alternatively, an image of the object can be obtained bysubtracting suitably normalized radiation data, or an estimate thereof,from the backscatter data collected by the detector.

FIG. 3 is a schematic illustrating a system configuration which can beused for snapshot backscatter radiography (SBR), according to anembodiment of the invention. A snapshot backscatter radiography (SBR)system 300 includes at least one penetrating radiation source 310 and atleast one radiation detector 320, such as a flexible detector sheet. TheSBR system 300 can be configured using commercially available radiationgenerators and detectors. Similar to backscatter radiography, both theradiation source 310 and the radiation detector 320 are disposed on thesame side of the object 330 which includes internal detail 332. Thesurface of the object or the surface of the medium covering the object,such as the earth, is indicated as reference 335.

System 300 can include a radiation source controller 350 and computer360. Computer 360 preferably includes memory and provides various systemfunctions, such as producing data representing an image of the objectinterrogated based on radiation data detected by detector 320. A displayscreen 380 for representing an image of the object interrogated is alsopreferably provided.

The radiation detector 320 is preferably a digitizing radiationdetector-film screen. In this embodiment, computer 350 has at leastmodest speed and data storage capacity for data processing and drivingdisplay 380.

Using the invention, two-dimensional (2D) or three-dimensional (3D) datasufficient to generate an image of the internal structure of objectscapable of scattering a portion of incident radiation is acquired in asnapshot illumination of an interrogated area of the object surface.Image data for 2D back-projections can be acquired in a single radiationgenerator/source burst.

Image data for a 3D display can be acquired if a temporal sequence ofdata sets is obtained at varying x-ray generator voltages. Highervoltages produce higher energy radiation which penetratescorrespondingly deeper into the object. The idea of photon spectrumtomography (Towe & Jacobs, X-ray Backscatter Imaging, IEEE Trans., onBiomed.-Engr., BME-28, p. 646-650, 1981) can be exploited to create a 3Dimage of the interrogated object internal structure. A pulsed radiation(e.g. x-ray) generator with a significant photon energy spectrumvariation over the pulse duration provides a useful method of obtainingsuch information in a single photon source pulse. In this embodiment,the temporal resolution of the detector would need to be sufficient toacquire this 3D image data in a single pulse. Otherwise, temporal gatingcould be employed for a sequence of generator pulses.

System 300 is generally contained in a protective and supportive housing345, which is preferably made from aluminum, or other suitablelightweight materials. Housing 345 holds the various components ofsystem 300 in place. Lightweight housing materials facilitateportability of system 300, which can be advantageous in certainapplications. The front of housing 390 as well as detector 320 (e.g. athin sheet) are both preferably made from flexible materials to conformto a variety of desired shapes.

The spacing of detector 320 from source 310 generally depends on thearea to be illuminated. For most wide area applications, the spacingfrom source 310 to detector 320 is generally about the same order ofmagnitude as the length of detector 320.

The arrangement shown in FIG. 3 implies that the radiation/objectinteractions of primary consequence are scatterings, although absorptioncan also be significant. Radiation from the radiation source 310, shownby reference 315, is directed at detector 320 which detects forwardradiation 315. The detected radiation pattern is referred to herein asthe first-pass data. The detected first-pass data includes informationon the spatial variations of the illumination radiation field and thespatial variation of structure and sensitivity of the detector 320.

Detector 320 transmits a portion of the forward radiation received,shown as reference 325, which penetrates surface 335 and strikesinternal detail 332 of object 330. The detector medium is generally adetector sheet which provides an area which is at least equal to theillumination area provided by radiation source 310.

The internal detail 332 of object 330 then backscatters a portion of thetransmitted radiation 325, shown as reference 355. Preferably, object310 scatters (reflects) at least 5 to 30% of the illuminating fieldprovided by radiation source 310. For example, a portion of radiation325 is transmitted through object 330 and is identified in FIG. 3 astransmitted radiation 365. Radiation detector 320 detects some of thebackscattered radiation portion 355, the backscattered radiation patternreferred to herein as the second-pass data. Thus, the second-pass datais generated by the backscattered radiation field 355 which emerges fromthe object or other surface 335 after being scattered by the internalstructure of object 330. Data to obtain the desired image of object canbe computed by subtracting the first pass data, or an estimate thereof,from the total detector data measured which comprises the sum of thefirst and second pass radiation data which includes information on thespatial variations of the radiation field and structure of the detectoras well as information on the object structure. Alternatively, thedesired image can be obtained by subtracting suitably normalizedincident (first-pass) radiation data, or estimate thereof, from thebackscatter data collected by the detector.

It is expected that achievable detector medium penetration can be >80%,and object medium reflection >50%, resulting in an object internalintensity of >40% of the first-pass intensity. Under these conditions,about 8% of the photons 315 are used to provide data to create thedesired image of object 330. This calculation assumes that the energy ofthe photons are unchanged throughout the process. However, backscatterradiation energy is somewhat lower than transmitted radiation 325, whichis itself less than forward radiation 315. Lower backscatter radiationenergy can either enhance or decrease the level of the detectedbackscattered radiation field signal 355 depending on the object and thedetector composition.

The SBR method can utilize the steps of digitization of the radiationdata received by detector 320. A digital image of the object 330 canthen be obtained and displayed on screen 380 through simple datamanipulation, such as by computer 360. Digitization also permits digitalimage enhancement techniques to be applied to the radiation data.

Radiation source 310 can generally be any penetrating radiation source.Radiation source 310 preferably illuminates the entire area to beinterrogated. For example, radiation source 310 can comprise an x-raysource, gamma ray source, neutron source or electron beam source. Theradiation source 310 is controlled to provide a photon illumination(energy) spectrum averaged optical depth in object 330 to reach thedeepest structure detail desired in the image to be about unity (i.e.,one x-ray mean-free-path). In the case of an x-ray source, the generatorvoltage is chosen to provide the desired photon illumination (energy)spectrum. In addition, the radiation intensity provided by radiationsource 310 preferably is sufficiently low so as to not saturate detector320.

Generally, first pass reference (base) data is obtained without object330 and is stored, such as in memory provided by computer 360, prior tointerrogating object 330. To minimize drift, it is preferred the basedata be updated periodically, such as every day or two, or upon a changeof configuration, or a change in source energy. Since only a transmittedreference image is desired, the base radiation data is preferablyacquired in an environment which does not backscatter significantradiation back to detector 320. For example, a perfect absorbing mediumwould be ideal. In practice, an empty room may provide a low backscatterenvironment. The base radiation data can then be subtracted from theoverall radiation detected which includes information from both thedetector structure and the spatial variation of the radiation sourcefield as well as the object structure to provide data which permitsgeneration of the desired image of object 330.

A system 400 including one or more optional collimating sheets 445 isshown in FIG. 4. The plurality of collimator plates 445 are orientedessentially perpendicular to the surface of detector 420 and aredisposed between the detector and the object being interrogated beneathabsorptive strip 415. The collimating sheets 445 enhance the Comptonbackscatter imaging. (CBI) process for photons which experienceincreased migration along directions perpendicular to the illuminationdirection, such as along the imaged plane in SBR. This data acquisitionvariant can be helpful for the detection and imaging of small, lateralmaterial structure or defects along planes parallel to the objectsurface, such as feature 455, including small diameter channels, orthin, delaminated regions which are parallel to an object surface.Conventionally applied collimators can also be used to improve imageresolution by limiting beam spot size, but generally also increasemeasurement time.

System 400 includes an absorptive strip 415 which functions as a shutterwhich is disposed between the radiation source 410 and the radiationdetector 420. Absorptive strip 415 can comprise a lead strip. Absorptivestrip 415 blocks transmission of the forward radiation beam 465 over aportion of the area of detector 420. The beam transmitted throughdetector 420 is identified as reference 485. Housing 490 is alsoprovided.

The object (or volume interrogated) 430 shown includes a crack or othervoid which provides an airspace 455. Object 430 is shown buried in amedium having a surface 435. The object/medium arrangement isessentially analogous to the arrangement when a land mine is buried inthe earth. Land mines are known to include air gaps to permit the fusemechanism to function properly and to provide directional blasts.

Radiation reflected from object 430 is indicated as backscatter beam475. Airspace 455 permits significantly enhanced lateral migration ofradiation along its length. This lateral enhancement results in a largerpercentage of radiation transmitted through detector 420 to fit betweenlaterally positioned adjacent collimator plates and reach detector 420for detection as compared to when object 430 does not include airspace455. Thus, when the region being interrogated does not include anymeasurable airspace 455, the signal detected by detector 420 beneathreflective strip 415 will be significantly less as compared to whenobject 430 include airspace 455. Thus, system 400 can be used toidentify structures such as landmines, delaminations and otherstructures which provide significant air spaces.

SBR is well suited to planar object interrogation of surfaces for bothplacement of the detector and interpretation of the scattered radiationproduced image. Independent of the flexibility of the detector medium,it is estimated that SBR can provide useful images of internal structuredetails of objects if the image size dimension is less than aboutone-third the radius-of-curvature of the interrogated region objectsurface. If the detector (e.g. film) is sufficiently flexible to conformto the object surface, this limit should increase to about one-half, ormore, depending on the distance to the radiation (e.g. x-ray) generatorfocal spot from the object surface.

Radiography applications, wherein internal structure near the surface ofan object is to be imaged, can benefit significantly from thebackscatter point of view provided by SBR. However, unlike backscatterradiography, the radiation detector 320 is disposed in the radiationpath so that the radiation which reaches the object 330 first passesthrough the radiation detector 320. Disposing the detector 320 in theradiation path as shown in FIGS. 3 and 4 provides certain advantages. Inparticular, the ability to provide a snapshot image of object 330without the need for mechanical scanning of the radiation source orobject rotation.

The temporal history of radiation in SBR is unlike either conventionaltransmission radiography or conventional backscatter radiography. Sourcegeneration of penetrating radiation results in a first-pass throughdetector 320. This step is not provided in either conventionaltransmission radiography or backscatter radiography. Interaction withinternal structure of object 330 produces reflective scattering whichresults in a second-pass through radiation detector 320. This step issimilar to conventional backscatter radiography, although the radiationincident on the object is transmitted through the radiation detector inSBR, whereas the radiation incident on the object is provided directlyfrom the radiation source in conventional backscatter radiography.

A variety of image detection technologies can be used with theinvention. The detector 320 generally needs to store base image data.The detector needs to permit significant radiation to be transmittedtherethrough. The detector 320 also needs to be capable of receivingmultiple images, i.e., be reusable with a minimum of drift.

For example, in the case of x-ray radiography where a large area imageis desired, there are at least two available x-ray detector technologieswhich can be used with the invention. The photostimuable phosphor-basedimaging plate (commonly referred to as computed radiography, or CR), aswell as an amorphous silicon panel (ASP) conversion screen bonded to anarray of photosensitive diodes.

The CR imaging medium is generally thin, uniform, and flexible. X-raysensitivity and image spatial resolution are sufficient for mostapplications. Significant care must be exercised in the time betweenlatent image acquisition and photo stimulation in the image readingprocess including light exclusion. As the technique is conventionallyapplied, there is a separate image reader device and the imaging plate(film) is transferred from the x-ray illumination device to the readerfor image digitizing and display. For application of the CR method to anSBR system, it would be advantageous if image exposure, reading,digitization, and display were accomplished in the same deviceeliminating the physical transfer of the imaging plate in the process.

The geometric featureless quality and physical flexibility of the CRimage plate imply a uniform first-pass image and easily-obtainedconformity of image acquisition geometry to the object surface. Theseproperties imply relatively straight-forward analysis of the acquiredimage and post-acquisition processing (e.g., subtraction of thefirst-pass image).

Most ASP detectors are neither thin nor homogeneous, but there are panelmodels where the associated amplifiers and voltage supplies are placedto the side of the imaging area. Typical panels are heavily shieldedagainst x-ray penetration from the rear which negates the geometricnecessities of the SBR system.

A major advantage of an ASP detector-film is the inherent, single-stepimage acquisition process. Data from a sequence of images can beacquired and stored for processing. Image differences obtained from aseries of varying x-ray generator voltages can be employed to yield 3Dimages of internal structure. Image differences obtained from a seriesof x-ray generator pulses can also form the basis of analysis of thedynamic response of internal structure, such as suggested in thedevelopment of dynamic radiography (Kenney & Jacobs, Research Techniquesin Nondestructive Testing, Chapter 6, p.217-243, Edited by Sharpe,Academic Press, 1977). With sufficient temporal resolution of the panel,a single x-ray generator pulse with time-varying spectrum can beemployed to efficiently acquire data for either of these applications.

CCD or other chip-based detectors may also be use with the invention inapplications where a large area image is not required. Chip baseddetectors are generally useful when the area to be interrogated isrelatively small, such as on the order of several ems, tens of μms, orhundreds of μms, such as a region on an integrated circuit.

The equivalent of an optical snapshot camera is often desirable for manyapplications, but has previously only been available using conventionaltransmission radiography. Unlike conventional transmission radiographywhich uses transmitted radiation, the SBR system and method describedherein advantageously enables snapshot radiography utilizing reflectedradiation, for example for applications where a detector cannot beplaced behind the object to be interrogated. The compact size, simplesystem configuration, and small time increment for image dataacquisition, all contribute to efficiency accuracy and viability of manydiagnostic and/or process control applications for SBR.

A clear benefit of the SBR approach is for radiography applications inwhich there is only one-sided access to the object. For example,scanning electron microscopes (SEM) are commonly used in integratedcircuit failure analysis and some process control which requiresresolution beyond that provided by standard optical inspections. Onereason for common use of SEMs in integrated circuit processing isbecause of high image resolution compared to standard optical inspectiontools. Moreover, transmission radiography is generally not possible forinterrogating integrated circuits due to the presence of one or moreheavily absorptive surfaces. For example, gold may coat the backside ofthe chip. Significantly, unlike SBR systems which can interrogate belowthe surface of a sample, conventional SEMs cannot interrogate regionsbelow the surface. In addition, SBR systems are expected to beinexpensive relative to SEMs. As noted above, the SBR system can provideimproved image resolution, and provide a resolution comparable to thatobtainable from conventional SEMs by including one or more collimatorssystem to reduce the beam size as required for the desired resolutionlevel.

The invention is also helpful where an internal structure element isdifficult, or impossible, to image by conventional transmissionradiography or even conventional backscatter radiography because ofamplification of image contrast during the subsurface migration, such aslateral migration, of the interrogating radiation produced by SBR whichcan be selectively sensed by proper design of the radiation detectorcomponents.

The invention is expected to have a variety of applications as itenables rapid snapshot images of an object or volume of interest and canalso be a portable system. For example, the invention can be used as aland mine detection system, for either military or humanitarian use toidentify buried land mines. Most buried land mines are made ofpredominantly plastic which makes it almost impossible to detect themines accurately with conventional detection techniques. Using the SBRsystem and method, explosives and plastics reflect more photons thansoil does, and scatter the photons more widely, which can create moreaccurate images of the mines. Rocks, wood, roots and other materialscreate very different images and are generally not confused with landmines using SBR.

The system can be small and lightweight, making it readily mobile. Thus,soldiers can carry an SBR system and interrogate the path in front ofthem before proceeding. Alternatively, landmine detectors can mounted ona vehicle to create mobile land mine detectors.

In addition, the invention is expected to be useful for rapidlyscreening articles within containers, such as luggage or cargo enteringairports. As compared to current x-ray based conventional transmissionor backscatter scanning detectors, the invention is expected to bemanufacturable at a significantly reduced cost since it does not requiremechanical scanning of the object or any system component. In addition,the SBR system can be portable, and provide images faster thanconventional scanning systems. As noted above, the SBR system can alsodetect explosives, such as plastic explosive, that are generallyundetectable by conventional systems used at airports.

EXAMPLE

The present invention is further illustrated by the following example.The example is provided for illustration only and is not to be construedas limiting the scope or content of the invention in any way.

SBR was tested in a single measurement which successfully imaged ahigh-contrast feature in an optimal configuration of an SBR system usingx-rays and a computed radiography (CR) screen detector with theassociated image reader replacing the image-analyzing computer. Theobject (and “structure”) was a plastic block on the interrogated surfacewhich included a small (1 cm×1 mm×0.1 mm thick) strip of lead. From theSBR image obtained the lead strip was clearly visible, with about 0.1 mmresolution provided.

It is to be understood that while the invention has been described inconjunction with the preferred specific embodiments thereof, that theforegoing description as well as the examples which follow are intendedto illustrate and not limit the scope of the invention. Other aspects,advantages and modifications within the scope of the invention will beapparent to those skilled in the art to which the invention pertains.

We claim:
 1. A snapshot backscatter radiography (SBR) system,comprising: at least one penetrating radiation source, and at least oneradiation detector, wherein said radiation detector is interposedbetween an object to be interrogated and said radiation source, saidradiation detector transmitting a portion of incident radiation fromsaid radiation source to said object, wherein a portion of radiationscattered by said object is detected by said detector.
 2. The system ofclaim 1, wherein said penetrating radiation source comprises at leastone selected from the group consisting of an x-ray, gamma ray, neutronand electron beam source.
 3. The system of claim 1, wherein saiddetector comprises a digitizing field screen.
 4. The system of claim 1,further comprising a computer for receiving radiation data from saiddetector and for performing data and image processing.
 5. The system ofclaim 1, wherein said system provides 3 dimensional (3-D) radiationimage data.
 6. The system of claim 5, further comprising a radiationsource controller.
 7. The system of claim 6, wherein said radiationsource controller directs said radiation source to provide at least oneof multiple bursts at varying radiation energy or temporal variation ofa radiation energy spectrum provided by said radiation source.
 8. Thesystem of claim 1, wherein said detector comprises a photostimuablephosphorous-based image plate.
 9. The system of claim 1, wherein saiddetector comprises an amorphous silicon panel.
 10. The system of claim1, wherein at least one collimating sheet is disposed between saidobject and said detector.
 11. The system of claim 1, wherein said objectcomprises an integrated circuit.
 12. A snapshot backscatter radiography(SBR) based land mine detection system, comprising: at least onepenetrating radiation source, and at least one radiation detector,wherein said radiation detector is interposed between a volume of earthto be interrogated and said radiation source, said radiation detectortransmitting a portion of incident radiation from said radiation sourceto an object buried in said volume of earth, wherein a portion ofradiation scattered by said object is detected by said detector.
 13. Thesystem of claim 12, wherein said radiation source comprises an x-raysource.
 14. The system of claim 12, wherein said system furthercomprises a vehicle.
 15. A snapshot backscatter radiography (SBR) basedluggage or cargo screening system, comprising: at least one penetratingradiation source, and at least one radiation detector, wherein saidradiation detector is interposed between luggage or cargo to beinterrogated and said radiation source, said radiation detectortransmitting a portion of incident radiation from said radiation sourceto said luggage or cargo, wherein a portion of radiation scattered bysaid luggage or cargo is detected by said detector.
 16. A snapshotbackscatter radiography (SBR) based integrated circuit inspection tool,comprising: at least one penetrating radiation source, and at least oneradiation detector, wherein said radiation detector is interposedbetween an integrated circuit to be interrogated and said radiationsource, said radiation detector transmitting a portion of incidentradiation from said radiation source to said integrated circuit, whereina portion of radiation scattered by said integrated circuit is detectedby said detector.
 17. The system of claim 16, wherein said detectorcomprises a CCD detector.
 18. The system of claim 16, wherein saidpenetrating radiation source provides selectable radiation energy,wherein a 3-D image of said integrated circuit can be obtained withoutphysical scanning by compiling radiation data at a plurality ofradiation energies.
 19. A snapshot backscatter radiography (SBR) methodfor imaging an object, comprising the steps of: directing penetratingforward radiation through a detector to an object to be interrogated,said detector transmitting a portion of said penetrating radiation tosaid object, wherein said object backscatters radiation toward saiddetector, and generating an image of said object.
 20. The method ofclaim 19, wherein said forward radiation comprises multiple bursts atvarying radiation energy, said method further comprising the step offorming a 3-D image of said object.
 21. The method of claim 19, whereinat least one collimating sheet is disposed between said object and saiddetector, further comprising the step of collimating at least one ofsaid forward radiation and said backscattered radiation.
 22. The methodof claim 19, further comprising the step of applying a deconvolvingimage enhancement technique to reduce image blurring.
 23. The method ofclaim 19, wherein said image is formed by subtracting said forwardradiation detected at said detector or an estimate of said forwardradiation detected at said detector from all radiation detected by saiddetector.
 24. The method of claim 19, wherein said image is formed bysubtracting normalized forward radiation data detected at said detectoror an estimate thereof, from backscatter radiation detected by saiddetector.